Remote-control apparatus with automatic limit provision



July 12, 1949. M. N. YARDENY REMOTE-CONTROL APPARATUS WITH AUTOMATIC LIMIT PROVISION Filed July 27, 1945 INVENTOR svyflvd ATTORNEY ?atented July 12, 1949 UNITED STATES PATENT OFFICE REMOTE-CONTROL APPARATUS WITH AUTOMATIC LIMIT PROVISION 4 Claims. 1

This invention relates to remote control apparatus of the follow-up type for placing, from a control point, a load at a remote point in ant desired position by means of the energization of an electric motor at the remote point.

It is inherent in the design of remote control apparatus of the follow-up type that, while the position of the load can be controlled from a con trol point and the load can be placed in any desired position, the position of the load at any given moment during the positioning of the load does not bear any definite relation to the posi tion of the control device. As a result, the load may be moved into a position which will cause damage to the load, for instance, the movable plates of a variable capacitor may be forced beyond their limit positions.

One object of the invention is to provide limit means for a follow-up system by which the load is automatically stopped when reaching a limit position independently of a further manipulation of the control device.

Another object is to provide a remote control apparatus with automatic limit positions, as described, with means for braking the motor when deenergized.

For the attainment of these and such other objects as may appear or be pointed out herein, there is shown an embodiment of the invention in the single figure which is a diagrammatic illustration. of the remote control system provided with the aforementioned improved features.

The control device at the control point comrises a pair of relatively movable members, one of which is an insulated disc 20 and the other a contact arm 10, both of which are mounted for rotation about a spindle 9. Insulated (1180 20 carries a pair of electrical conducting elements in the form of segments 2|, 22 adjacent ends of which are separated by a gap I9, I 9. Conducting elements 2|, 22 are connected to collector rings, respectively, 23, 24, engaged by respective stationary brushes 25 26 which are connected by leads 25, 26 to the outer terminals of a pair of relays 21, 28. The inner terminals of relays 21, 28 are connected by short leads 21 28 to a lead 29, connected to a wire 8 leading through a switch 23 to one terminal 1 of a source of current.

The contact arm IE] is provided with a distal contact element NI which is slidably engageable with the conducting segments 2|, 22 and is connected at its proximal end by a lead 6 to a supply wire connected through a switch 5s to the other terminal 4 of the current source. Contact arm 10 is selectively adjusted to engage one or the other of the contact elements 2|, 22 to energize the proper one of the relays 21, 28 to cause motor rotation in the desired direction. For example, if contact arm II) is adjusted, by manipulating knob 10k, counter-clockwise from the position shown in the figure to engage conducting element 2!, a circuit will be completed through relay 21, which circuit may be traced from one supply terminal 4, through lead 6, contact arm [0, engaged segment 21, collector ring 23 and brush 25 lead 25, to the outer terminal of relay 21, from whence through short lead 21 and common lead 29, to wire 8 leading to the other supply terminal 1.

Energization of one or the other of the relays 21, 28 causes energization of the respective ones of the field windings, 48 of load motor 40 and respective windings 31, 38 of the pilot motor 3c, the function of which is to turn one of the pair of relatively movable members (in the illustration shown, the insulated disc 20) in a direction to cause realignment of gap 19 and contact element 10 of the contact arm ID to cause stopping of load motor rotation. For this purpose, shaft ii of pilot motor 30 is provided with a pinion p which meshes with a gear 20g secured to rotate with the insulated disc 20.

The armatures of the relays 21, 28 are effective to energize respective ones of the field windings 31, 38 of pilot'motor 30, and field windings 41, 48 of load motor 40, depending upon which one of the relays is energizedin the following manner: Each of the relays 21, 28 is provided with a pair of armatures, the armature associated with relay 21 being an inner armature I5 and an outer armature 11; the armatures associated with the other relay 28 include an inner armature M and an outer armature I6. The armatures are shown in the figure in their unattracted position when both relays 21, 28 are deenergized. It has been described above that engagement of the contact arm ID with conducting segment 21 results in energization of relay 21. Energization of relay 21 attracts its both armatures l5, l1 to complete a circuit to field windings 31 and 41, respectively, of the pilot motor 30 and of the load motor 43. The circuit to field winding 31 of the pilot motor 30 may be traced from one supply wire 5, through a lead I, to a contact 2 associated with the relay 28, through the unattracted armature 14 of deenergized relay 28, a short lead I3 connecting the proximal ends of the armatures I 4, l5, attracted armature 15 of energized relay 21, a contact 35 of relay 21, lead 36 to the outer terminal of field winding 31, from the common winding terminal, through a lead 32, to the other supply wire 8. Simultaneously with the energization of field winding 31 of pilot motor 30, field windings 41 of load motor 40 is energized through the completion of a circuit which may be traced from the short lead l3 connecting the proximal ends of armatures |4, |5, which is connected, as already traced, to the supply wire 5, through a short lead I2, lead H, to a contact 19 associated with relay 21, through attracted armature ll of energized relay 27, short leads II |6 unattracted armature N of deenergized relay 28, a contact 45 of relay 28, lead 48, to the outer terminal of field winding 41 of load motor 48, from th inner common terminal thereof through a lead 8' to the other supply wire 8.

Load motor 48 is provided with a pinion 40p meshing with a gear 509 secured to rotate with the load 58. Energization of field winding 41 of load motor 40 causes turning of the load in the desired direction. Energization of field winding 31 of pilot motor causes rotation of the pilot motor in a clockwise direction to cause the insulated disc 28 to be turned in acounterclockwise direction to bring gap |0 into alignment with the contact arm II! which had been assumed to be turned counter-clockwise to engage conducting segment 2|. It will be noted from the figure that when the gap I9 is aligned with contact arm 18, the contact element 18 bridges the gap so as to engage both conducting segments 2!, 22 simultaneously. This causes energization of both relays 27, 28 to cause attraction of their armatures. resulting in breaking of the circuit to both the pilot motor 38 and the load motor 40. adjustment of the contact arm ID in a clockwise direction to engage the other segment 22 causes energization of the other relay 28, to energize the other field winding 38 of the pilot motor and the other field winding 48 of the load motor by completion of circuits similar to the ones traced in the instance when relay 2! is energized.

The system is further provided with an electromagnetic brake illustratively represented by its coil 39 adapted to positivelystop .the rotation of the pilot motor 30 automatically when both field windings 31, 38 are deenergized. The coil .39 of the electromagnetic brake is connected in a circuit which may be traced from the common terminal of the field windings 31, 38 through a short lead 39 through the electromagnet coil 39 and by a lead 34 to the juncture of the aforementioned short leads HX, |6 connecting armatures l1, IS. The electromagneti brake is designed to spring press its braking element into operative position to stop motor rotation when its electromagnetic coil is deenergized and to withdraw the braking element when the coil is energized. When either one of the armatures IT, I5 is in attracted position to complete a circuit to one or the other of'the windings 41, 48 of the load motor 40 and when one-or the other of the field windings 31, 38 of the pilot motor 30 is energized, a circuit will becompleted from supply wire 5, as previously traced, to the short lead I'I |6 and through the lead 34 to pass through the electromagnetic coil, continuing through short lead 39 and lead 32 to the'other supply wire 8; hence, when the field windings 0f the motorsare energized for directional rotation of the respective motors, the electromagnetic coil 39 will be energized to withdraw its braking element. When the motors are stopped by bridgingof the gap I9, in the manner already described to cause energization of both relays 21, 28, and the open- Selective ing of the circuits to the field windings of both motors, the circuit through electromagnet 39 will likewise be broken and the spring thus rendered operative to stop the rotation of the pilot motor. A similar automatic electromagnetic brake may be applied to the load motor, if desired.

The load 58, for purposes of illustration shown in the figure in the form of a rotative disc, has a limited extent of angular movement of between contact 5| and contact 52. Contact 5| is connected by lead 53 to the lead 25 which, as already described, connects the outer terminal of relay 2"! with the collector ring 23 associated with conducting segment 2 I; the other limit con tact 52 is connected by a lead 54 to the lead 26 which connects the outer terminal of the other relay 28 with the collector ring 24 associated with the other conducting segment 22. The load, represented by disc 50, is connected at its proximal point by lead 5 to the supply wire 5 and is further provided at its periphery with a contact 50 When the load disc 58, in turning, for example, in a counter-clockwise direction,--as a result of energization of field winding 4'! and the energization of relay 21 (by reason of the circuit already traced), reaches the limit of its range of restricted movement defined by the contact 52, the contact 58 secured to rotate with the load disc 50, engages the contact 52 to complete a circuit to energize the other relay 28. This circuit may be traced from supply wire 5, through lead 5', contact 52, lead 54, lead 26, to the outer terminal of relay 28, from the inner terminal thereof, through short lead 28 and lead 29, to the other supply wire '8.

Relay 2! already being energized to cause the said counter-clockwise rotation of the load, the energization of the other relay 28 will cause both relays to be energized and their armatures to be attracted and thus to disconnect the cir cuits to both load motor 40 and the pilot motor 30, thus causing the load to be stopped at the limit defined by limit contact 52. Similarly the load will be stopped at the limit defined by limit contact 5| during rotation in a clockwise direction when relay 28 is energized.

The advantage of conecting limit contacts 5|, 52 in the manner described to cause the energization of the relay other than the one energized to cause the load rotation in the desired direction and thus to energize both relays, resides in the fact that under no circumstances can there occur a reversal in motor direction. For example, should the contact arm l0 align with the gap If], at a time just preceeding the engagement of the load contact 50 with one or the other of the limit contacts 5|, 52, there would occur a reversal in motor rotation if the alignment were such that upon engagement of 50 with one or the other of the contacts 5|, 52 the respective relay were to be deenergized. The alignment of gap l9 and contact arm it causes the energization of both relays H, 28. I If the arrangement were such that the engagement with one or the other of the limit switches 5|, 52 resulted in a deenergization or the respective relays, then th othr relay would remain energized and cause rotation of the load motor (and also the pilot motor) in the reverse direction. By providing that the limit switches 5|, 52 cause energization of respective ones of the relays 2T, 28, this could never occur even when both relays are energized by the alignment of ap l9 and contact arm 10.

I claim:

1. In a remote control device of the follow-up type for moving a load in either direction to de sired positions, in combination, a reversible motor for moving the load, a pair of movable members, one of the members having a pair of electrical conducting elements separated by a gap and the other member having a contact element engageable therewith, a pilot motor operatively connected with one of the said pair of members for moving the same, a pair of relays connected in circuit with respective ones of the said conduct ing elements and controlling circuits for the load motor and the pilot motor, the other of the said pair of movable members being selectively mova" ble by other means to engage the said contact element with one or the other of the said co ductingelements to energize its respective relay for directional rotation of the said load motor and pilot motor, rotation of the pilot motor turn ing the first said member in a direction to re" align said contact element and gap and engage the said contact element With both conducting elements to energize both relays, thereby stopping motor rotation, a contact secured to rotate with. the said load, and limit contacts connected in circuit with respective ones of the said pair of relays, said limit contacts being positioned to be engaged by the rotating contact for energizing the relay other than the one energized by the said engagement of contact element and conducting elementswhereby both relays are energized to stop motor rotation.

2. In a remote control device of the follow-up type for moving a load in either direction to de sired positions in combination, a reversible motor for moving the load, a pair of movable members, one of the members having a pair of electrical conducting elements separated by a gap and the other member having a contact element engageable therewith, a drive means operatively connected with one of the said pair of members for moving the said member, a pair of relays connected in circuit with respective ones of the said conducting elements, the other of the said pair of relatively movable members being selectively adiustable by other means to engage the said contact element with one or the other of the said conducting elements to energize its respective relay for dirctional rotation of the said load motor, the said drive means being arranged to turn the first said member in a direction to re-align said contact element and gap and engage the said contact element with both conducting elements to energize both relays to stop motor rotation, a contact secured to rotate with the said load, and limit contacts connected in circuit with respective ones of the said pair of relays, said limit contacts being positioned to be engaged by the rotating contact for energizing the relay other than the one energized by the said engagement of contact element and conducting elements, whereby both relays are energized to stop motor rotation.

3. In a remote control device of the follow-up type for moving a load in either direction to desired positions, in combination, a reversible motor for moving the load, a pair of movable members, one of the members having a pair of electri cal conducting elements separated by a gap and the other member having a contact element en'- gageable therewith, a pilot motor operatively con nected with one of the said pair of members, a pair of relays connected in circuit with respective ones of the said conductingelements, the other of the said pair of relatively movable members being manually adjustable to engage the said contact element with one or the other of the said conducting elements to energize its respective relay for directional rotation of the said lead motor and pilot motor, rotation of the pilot motor turning the first said member in a direction to re-align and contact element and gap and engage the said contact element with both conducting elements to energize both relays to stop motor rotation, limit switches connected in circuits with respective ones of the said pair of relays, and means secured to rotate with the said load for actuating the said limit switches to energize the relay other than the one energized by the said engagement of contact element and conducting elements, whereby both relays are energized to stop rotation of both motors.

4. In a device of the follow-up type at a control point for moving a load at a remote point in either direction to desired positions, in combination, a reversible motor for moving the load, relays electrically connected to control the directional rotation of the motor, a device at the control point having a pair of relatively movable members, one of the members being manu ally adjustable to energize the relays for the desired direction of motor rotation, a pilot motor at the control point electrically connected to be controlled by the said relays for moving the other member into a direction and positioned to control the relays to stop rotation of said load and pilot motors, limit switches electrically connected to the said relays, and contact means secured to rotate with the load for actuating the switches to control the relays for stopping rotation of said load and pilot motors when the load contact has reached one of the said two limit contacts.

MICHEL N. YARDENY.

REFERENCES CITED The following referenrces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 714,862 Buck Dec. 2, 1902 803,209 Bates Oct. 31, 1905 1,853,506 Carter Apr. 12, 1932 2,201,868 Moffett May 21, 1940 2,377,286 White May 29, 1945 FOREIGN PATENTS Number Country Date 510,596 Great Britain July 31, 1939 

